Nambayar found a dinosaur egg, a fossil of a recent discovery in Mongolia, except that by installing the egg in the incubator that Jett and Jett Pet brought her, Coco, a baby tyrannosaurus rex, is born. With Storm's help, Jett, also with Dizzy and Donnie and their Super Pets, set off in Jurassic period to try and find Coco's mother. Except that several adventures put them to the test (a brachiosaur which is stamped in a rock wall, several dinosaurs at risk of falling from a precipice). It wasn't until Storm came to the rescue with Jett and Donnie's robot suits that Coco finally found her mother, who was chasing Golden Boy, also present.